1. Field of the Invention
This invention relates to sampling frequency conversion.
2. Description of the Prior Art
It is known to use sampling frequency converters in applications such as conversion between sampling frequencies associated with different pulse code modulation (PCM) audio signal transmission systems. Sampling frequency conversion is particularly useful in a digital audio recording or editing studio in order to provide an interface between items of digital audio equipment operating at different sampling frequencies, without having to convert to and from an intermediate analogue signal. Although items of equipment operating at the same nominal sampling frequency can generally be synchronised with a `master` clocking signal distributed from a single source to those items, there still remains a need for sampling frequency conversion in that several different sampling frequency standards are used in current digital audio equipment (e.g. 32 kHz, 44.056 kHz, 44.1 kHz, 48 kHz).
A sampling frequency converter disclosed in EP-A-0 323 200 employs a stage of oversampling the input data samples by an integral oversampling factor before sampling frequency conversion, and a stage of downsampling by an integral downsampling factor after sampling frequency conversion.